[pull] main from python:main

Doc/library/stdtypes.rst

@@ -1286,7 +1286,7 @@ Mutable sequence types also support the following methods:
    :no-typesetting:
 .. method:: sequence.append(value, /)
 
-   Append *value* to the end of the sequence
+   Append *value* to the end of the sequence.
    This is equivalent to writing ``seq[len(seq):len(seq)] = [value]``.
 
 .. method:: bytearray.clear()

Lib/asyncio/base_events.py

@@ -19,14 +19,15 @@
 import errno
 import heapq
 import itertools
+import math
 import os
 import socket
 import stat
 import subprocess
+import sys
 import threading
 import time
 import traceback
-import sys
 import warnings
 import weakref
 
@@ -2022,7 +2023,10 @@ def _run_once(self):
         event_list = None
 
         # Handle 'later' callbacks that are ready.
-        end_time = self.time() + self._clock_resolution
+        now = self.time()
+        # Ensure that `end_time` is strictly increasing
+        # when the clock resolution is too small.
+        end_time = now + max(self._clock_resolution, math.ulp(now))
         while self._scheduled:
             handle = self._scheduled[0]
             if handle._when >= end_time:

Lib/test/test_types.py

@@ -2168,6 +2168,21 @@ class Spam(types.SimpleNamespace):
         self.assertIs(type(spam2), Spam)
         self.assertEqual(vars(spam2), {'ham': 5, 'eggs': 9})
 
+    def test_replace_invalid_subtype(self):
+        # See https://github.com/python/cpython/issues/143636.
+        class MyNS(types.SimpleNamespace):
+            def __new__(cls, *args, **kwargs):
+                if created:
+                    return 12345
+                return super().__new__(cls)
+
+        created = False
+        ns = MyNS()
+        created = True
+        err = (r"^expect types\.SimpleNamespace type, "
+               r"but .+\.MyNS\(\) returned 'int' object")
+        self.assertRaisesRegex(TypeError, err, copy.replace, ns)
+
     def test_fake_namespace_compare(self):
         # Issue #24257: Incorrect use of PyObject_IsInstance() caused
         # SystemError.

Misc/NEWS.d/next/Core_and_Builtins/2026-01-10-12-59-58.gh-issue-143636.dzr26e.rst

@@ -0,0 +1,2 @@
+Fix a crash when calling :class:`SimpleNamespace.__replace__()
+<types.SimpleNamespace>` on non-namespace instances. Patch by Bénédikt Tran.

Misc/NEWS.d/next/Library/2026-03-09-19-59-05.gh-issue-145703.4EEP7J.rst

@@ -0,0 +1,3 @@
+:mod:`asyncio`: Make sure that :meth:`loop.call_at <asyncio.loop.call_at>` and
+:meth:`loop.call_later <asyncio.loop.call_later>` trigger scheduled events on
+time when the clock resolution becomes too small.

Objects/namespaceobject.c

@@ -13,6 +13,7 @@ typedef struct {
 } _PyNamespaceObject;
 
 #define _PyNamespace_CAST(op) _Py_CAST(_PyNamespaceObject*, (op))
+#define _PyNamespace_Check(op) PyObject_TypeCheck((op), &_PyNamespace_Type)
 
 
 static PyMemberDef namespace_members[] = {
@@ -234,6 +235,14 @@ namespace_replace(PyObject *self, PyObject *args, PyObject *kwargs)
     if (!result) {
         return NULL;
     }
+    if (!_PyNamespace_Check(result)) {
+        PyErr_Format(PyExc_TypeError,
+                     "expect %N type, but %T() returned '%T' object",
+                     &_PyNamespace_Type, self, result);
+        Py_DECREF(result);
+        return NULL;
+    }
+
     if (PyDict_Update(((_PyNamespaceObject*)result)->ns_dict,
                       ((_PyNamespaceObject*)self)->ns_dict) < 0)
     {